Rapamycin hydroxyesters

ABSTRACT

A compound of the structure 
     
       
         
         
             
             
         
       
         
         wherein R 1  and R 2  are each, independently, hydrogen or —CO(CR 3 R 4 ) b (CR 5 R 6 ) d CR 7 R 8 R 9 ; 
         R 3  and R 4  are each, independently, hydrogen, alkyl, alkenyl, alkynyl, trifluoromethyl, or —F; 
         R 5  and R 6  are each, independently, hydrogen, alkyl, alkenyl, alkynyl, —(CR 3 R 4 ) f OR 10 , —CF 3 , —F, or —CO 2 R 11 , or R 5  and R 6  may be taken together to form X or a cycloalkyl ring that is optionally mono-, di-, or tri-substituted with —(CR 3 R 4 ) f OR 10 ; 
         R 7  is hydrogen, alkyl, alkenyl, alkynyl, —(CR 3 R 4- ) f OR 10 , —CF 3 , —F, or CO 2 R 11 ; 
         R 8  and R 9  are each, independently, hydrogen, alkyl, alkenyl, alkynyl, —(CR 3 R 4 ) f OR 10 , —CF 3 , —F, or —CO 2 R 11 , or R 8  and R 9  may be taken together to form X or a cycloalkyl ring that is optionally mono-, di-, or tri-substituted with —(CR 3 R 4- ) f OR 10 ; 
         R 10  is hydrogen, alkyl, alkenyl, alkynyl, tri-(alkyl)silyl, tri-(alkyl)silylethyl, triphenylmethyl, benzyl, alkoxymethyl, tri-(alkyl)silylethoxymethyl, chloroethyl, or tetrahydropyranyl; 
         R 11  is hydrogen, alkyl, alkenyl, alkynyl, or phenylalkyl; 
         X is 5-(2,2-dialkyl)[1,3]dioxanyl, 5-(2,2-dicycloalkyl)[1,3]dioxanyl, 4-(2,2-dialkyl)[1,3]dioxanyl, 4-(2,2-dicycloalkyl)[1,3]dioxanyl, 4-(2,2dialkyl)[1,3]dioxalanyl, or 4-(2,2-dicycloalkyl)[1,3]dioxalanyl; 
         b=0-6; 
         d=0-6; and 
         f=0-6
 
with the proviso that R 1  and R 2  are both not hydrogen and further provided that either R 1  or R 2  contains at least one —(CR 3 R 4 ) f OR 10 , X, or —(CR 3 R 4 ) f OR 10  substituted cycloalkyl group, or a pharmaceutically acceptable salt thereof which is useful as an immunosuppressive, antiinflammatory, antifungal, antiproliferative, and antitumor agent.

This application is a reissue application of U.S. Pat. No. 5,362,718,issued Nov. 8, 1994, which issued from U.S. application Ser. No.08/229,261, filed Apr. 18, 1994.

BACKGROUND OF THE INVENTION

This invention relates to hydroxyesters of rapamycin and a method forusing them for inducing immunosuppression, and in the treatment oftransplantation rejection, graft vs. host disease, autoimmune diseases,diseases of inflammation, adult T-cell leukemia/lymphoma, solid tumors,fungal infections, and hyperproliferative vascular disorders.

Rapamycin is a macrocyclic triene antibiotic produced by Streptomyceshygroscopicus, which was found to have antifungal activity, particularlyagainst Candida albicans, both in vitro and in vivo [C. Vezina et al.,J. Antibiot. 28, 721 (1975); S. N. Sehgal et al., J. Antibiot 28, 727(1975); H. A. Baker et al., J. Antibiot. 31,539 (1978); U.S. Pat. Nos.3,929,992; and 3,993,749].

Rapamycin alone (U.S. Pat. No. 4,885,171) or in combination withpicibanil (U.S. Pat. No. 4,401,653) has been shown to have antitumoractivity. R. Martel et al, [Can. J. Physiol. Pharmacol. 55, 48 (1977)]disclosed that rapamycin is effective in the experimental allergicencephalomyelitis model, a model for multiple sclerosis; in the adjuvantarthritis model, a model for rheumatoid arthritis; and effectivelyinhibited the formation of IgE-like antibodies.

The immunosuppressive effects of rapamycin have been disclosed in FASEB3, 3411 (1989). Cyclosporin A and FK-506, other macrocyclic molecules,also have been shown to be effective as immunosuppressive agents,therefore useful in preventing transplant rejection [FASEB 3, 3411(1989); FASEB 3, 5256 (1989); R. Y. Calne et al., Lancet 1183 (1978);and U.S. Pat. No. 5,100,899].

Rapamycin has also been shown to be useful in preventing or treatingsystemic lupus erythematosus [U.S. Pat. No. 5,078,999], pulmonaryinflammation [U.S. Pat. No. 5,080,899], insulin dependent diabetesmellitus [Fifth Int. Conf. Inflamm. Res. Assoc. 121 (Abstract), (1990)],smooth muscle cell proliferation and intimal thickening followingvascular injury [Morris, R. J. Heart Lung Transplant 11 (pt. 2): 197(1992)], adult T-cell leukemia/lymphoma [European Patent Application525,960 A1], and ocular inflammation [European Patent Application532,862 A1].

Mono- and diacylated derivatives of rapamycin (esterified at the 28 and43 positions) have been shown to be useful as antifungal agents (U.S.Pat. No. 4,316,885) and used to make water soluble aminoacyl prodrugs ofrapamycin (U.S. Pat. No. 4,650,803). Recently, the numbering conventionfor rapamycin has been changed; therefore according to ChemicalAbstracts nomenclature, the esters described above would be at the 31-and 42- positions.

DESCRIPTION OF THE INVENTION

This invention provides derivatives of rapamycin which are useful asimmunosuppressive, antiinflammatory, antifungal, antiproliferative, andantitumor agents having the structure

-   wherein R¹ and R² are each, independently, hydrogen or    —CO(CR³R⁴)_(b)(CR⁵R⁶)CR⁷R⁸R⁹;-   R³ and R⁴ are each, independently, hydrogen, alkyl of 1-6 carbon    atoms, alkenyl of 2-7 carbon atoms, alkynyl of 2-7 carbon atoms,    trifluoromethyl, or —F;-   R⁵ and R⁶ are each, independently, hydrogen, alkyl of 1-6 carbon    atoms, alkenyl of 2-7 carbon atoms, alkynyl of 2-7 carbon atoms,    —(CR³R⁴)_(f)OR¹⁰, —CF₃, —F, or —CO₂R¹¹, or R⁵ and R⁶ may be taken    together to form X or a cycloalkyl ring of 3-8 carbon atoms that is    optionally mono-, di-, or tri-substituted with —(CR³R⁴)_(f)OR¹⁰;-   R⁷ is hydrogen, alkyl of 1-6 carbon atoms, alkenyl of 2-7 carbon    atoms, alkynyl of 2-7 carbon atoms, —(CR³R⁴)_(f)OR¹⁰, —CF₃, —F, or    —CO₂R¹¹;-   R⁸ and R⁹ are each, independently, hydrogen, alkyl of 1-6 carbon    atoms, alkenyl of 2-7 carbon atoms, alkynyl of 2-7 carbon atoms,    —(CR³R⁴)_(f)OR¹⁰, —CF₃, —F, or —CO₂R¹¹, or R⁸ and R⁹ may be taken    together to form X or a cycloalkyl ring of 3-8 carbon atoms that is    optionally mono-, di-, or tri-substituted with —(CR³R⁴)_(f)OR¹⁰;-   R¹⁰ is hydrogen, alkyl of 1-6 carbon atoms, alkenyl of 2-7 carbon    atoms, alkynyl of 2-7 carbon atoms, tri-(alkyl of 1-6 carbon    atoms)silyl, tri-(alkyl of 1-6 carbon atoms)silylethyl,    triphenylmethyl, benzyl, alkoxymethyl of 2-7 carbon atoms,    tri-(alkyl of 1-6 carbon atoms)silylethoxymethyl, chloroethyl, or    tetrahydropyranyl;-   R¹¹ is hydrogen, alkyl of 1-6 carbon atoms, alkenyl of 2-7 carbon    atoms, alkynyl of 2-7 carbon atoms, or phenylalkyl of 7-10 carbon    atoms;-   X is 5-(2,2-di-(alkyl of 1-6 carbon atoms))[1,3]dioxanyl,    5-(2,2-di-(cycloalkyl of 3-8 carbon atoms))[1,3]dioxanyl,    4-(2,2-di-(alkyl of 1-6 carbon atoms))[1,3]dioxanyl,    4-(2,2-di-(cycloalkyl of 3-8 carbon atoms))[1,3]dioxanyl,    4-(2,2-di-(alkyl of 1-6 carbon atoms))[1,3]dioxalanyl, or    4-(2,2-di-(cycloalkyl of 3-8 carbon atoms))[1,3]dioxalanyl;-   b=0-6;-   d=0-6; and-   f=0-6    with the proviso that R¹ and R² are both not hydrogen and further    provided that either R¹ or R² contains at least one    —(CR³R⁴)_(f)OR¹⁰, X, or —(CR³R⁴)OR¹⁰ substituted cycloalkyl of 3-8    carbon atoms group, or a pharmaceutically acceptable salt thereof.

The pharmaceutically acceptable salts are those derived from suchinorganic cations such as sodium, potassium, and the like; and organicbases such as: mono-, di-, and trialkyl amines of 1-6 carbon atoms, peralkyl group and mono-, di-, and trihydroxyalkyl amines of 1-6 carbonatoms per alkyl group, and the like.

The terms alkyl of 1-6 carbon atoms, alkenyl of 2-7 carbon atoms, andalkynyl of 2-7 carbon atoms, include both straight chain as well asbranched carbon chains. As the compounds of this invention can containmore than one —(CR³R⁴)_(f)OR¹⁰ group, R³, R⁴, f, and R¹⁰ can be the sameor different. Similarly, when other generic substituent descriptions arerepeated in the same structure, they can be the same or different.

For a compound in which R¹ contains R⁸ and R⁹ taken together to form X,where X is 5-(2,2-di-(alkyl of 1-6 carbon atoms))[1,3]dioxanyl, thealkyl group of X contains 1 carbon atom, and d=0, R¹ would have thefollowing structure.

Similarly, for a compound in which R¹ contains R⁸ and R⁹ taken togetherto form X, where X is 4-(2,2-di-(cycloalkyl of 3-8 carbonatoms))[1,3]dioxanyl, the cycloalkyl group of X contains 6 carbon atom,and d=0, R¹ would have the following structure.

For compounds containing X, preferred compounds include those in whichthe alkyl group of X, if present, is methyl and the cycloalkyl group ofX, if present, is cyclohexyl.

When R¹⁰ is not hydrogen, alkyl, alkenyl, or alkynyl, it is intendedthat R¹⁰ is a group that can serve as an alcohol protecting group. Thus,these groups are intermediates of free hydroxylated compounds, as wellas being biologically active in their own right. R¹⁰ covers tri-(alkylof 1-6 carbon atoms)silyl, tri-(alkyl of 1-6 carbon atoms)silylethyl,triphenylmethyl, benzyl, alkoxymethyl of 2-7 carbon atoms, tri-(alkyl of1-6 carbon atoms)silylethoxymethyl, chloroethyl, and tetrahydropyranylgroups. Other alcohol protecting groups are known by one skilled in thean and are also considered pan of this invention.

Of the compounds of this invention preferred members are those in whichR² is hydrogen; those in which R² is hydrogen, b=0, and d=0; those inwhich R² is hydrogen, b=0, d=0, and R⁸ and R⁹ are each, independentlyhydrogen, alkyl, or —(CR³R⁴)_(f)OR¹⁰, or are taken together to form X.

Compounds of this invention having the ester group—CO(CR³R⁴)_(b)CR⁵R⁶)_(d)(CR⁷R⁸R⁹)_(e) at the 42- or 31,42-positions canbe prepared by acylation of rapamycin using protected hydroxy andpolyhydroxy acids, alkoxy or polyalkoxy carboxylic acids that have beenactivated, followed by removal of the alcohol protecting groups, if sodesired. Several procedures for carboxylate activation are known in theart, but the preferred methods utilize carbodiimides, mixed anhydrides,or acid chlorides. For example, an appropriately substituted carboxylicacid can be activated as a mixed anhydride, with an acylating group suchas 2,4,6-trichlorobenzoyl chloride. Treatment of rapamycin with themixed anhydride under mildly basic condition provides the desiredcompounds. Alternatively, the acylation reaction can be accomplishedwith 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride anddimethylaminopyridine. Mixtures of 42- and 31,42-esters can be separatedby chromatography.

The 31-ester-42-hydroxy compounds of this invention can be prepared byprotecting the 42-alcohol of rapamycin with a protecting group, such aswith a tert-butyl dimethylsilyl group, followed by esterification of the31-position by the procedures described above. The preparation ofrapamycin 42-silyl ethers is described in U.S. Pat. No. B1 5,120,842,which is hereby incorporated by reference. Removal of the protectinggroup provides the 31-esterified compounds. In the case of thetert-butyl dimethylsilyl protecting group, deprotection can beaccomplished under mildly acidic conditions, such as aceticacid/water/THF. The deprotection procedure is described in Example 15 ofU.S. Pat. No. 5,118,678, which is hereby incorporated by reference.

Having the 31-position esterified and the 42-position deprotected, the42-position can be esterified using a different acylating agent than wasreacted with the 31-alcohol, to give compounds having different estersat the 31- and 42- positions. Alternatively, the 42-esterifiedcompounds, prepared as described above, can be reacted with a differentacylating agent to provide compounds having different esters at the31-and 42-positions.

This invention also covers analogous hydroxy esters of other rapamycinssuch as, but not limited to, 29-demethoxyrapamycin, [U.S. Pat. No.4,375,464, 32-demethoxyrapamycin under C.A. nomenclature]; rapamycinderivatives in which the double bonds in the 1-, 3-, and/or 5-positionshave been reduced [U.S. Pat. No. 5,023,262]; 29-desmethylrapamycin [U.S.Pat. No. 5,093,339, 32-desmethylrapamycin under C.A. nomenclature];7,29-bisdesmethylrapamycin [U.S. Pat. No. 5,093,338,7,32-desmethylrapamycin under C.A. nomenclature]; and15-hydroxyrapamycin [U.S. Pat. No. 5,102,876]. The disclosures in theabove cited U.S. Patents are hereby incorporated by reference.

Immunosuppressive activity for representative compounds of thisinvention was evaluated in an in vitro standard pharmacological testprocedure to measure the inhibition of lymphocyte proliferation (LAF)and in two in vivo standard pharmacological test procedures. The pinchskin graft test procedure measures the immunosuppressive activity of thecompound tested as well as the ability of the compound tested to inhibitor treat transplant rejection. The adjuvant arthritis standardpharmacological test procedure, which measures the ability of thecompound tested to inhibit immune mediated inflammation. The adjuvantarthritis test procedure is a standard pharmacological test procedurefor rheumatoid arthritis. The procedures for these standardpharmacological test procedures are provided below.

The comitogen-induced thymocyte proliferation procedure (LAF) was usedas an in vitro measure of the immunosuppressive effects ofrepresentative compounds. Briefly, cells from the thymus of normalBALB/c mice are cultured for 72 hours with PHA and IL-1 and pulsed withtritiated thymidine during the last six hours. Cells are cultured withand without various concentrations of rapamycin, cyclosporin A, or testcompound. Cells are harvested and incorporated radio-activity isdetermined. Inhibition of lymphoproliferation is assessed as percentchange in counts per minute from nondrug treated controls. For eachcompound evaluated, rapamycin was also evaluated for the purpose ofcomparison. An IC₅₀ was obtained for each test compound as well as forrapamycin. When evaluated as a comparator for the representativecompounds of this invention, rapamycin had an IC₅₀ ranging from 0.6-1.5nM. The results obtained are provided as an IC₅₀ and as the percentinhibition of T-cell proliferation at 0.1 μM. The results obtained forthe representative compounds of this invention were also expressed as aratio compared with rapamycin. A positive ratio indicatesimmunosuppressive activity. A ratio of greater than 1 indicates that thetest compound inhibited thymocyte proliferation to a greater extent thanrapamycin. Calculation of the ratio is shown below.

$\frac{{IC}_{50}\mspace{14mu}\text{of~~Rapamycin}}{{IC}_{50}\mspace{14mu}\text{of~~Test~~Compound}}$

Representative compounds of this invention were also evaluated in an invivo test procedure designed to determine the survival time of pinchskin graft from male BALB/c donors transplanted to male C₃H(H-2K)recipients. The method is adapted from Billingham R. E. and Medawar P.B., J. Exp. Biol. 28:385-402, (1951). Briefly, as pinch skin graft fromthe donor was grafted on the dorsum of the recipient as a allograft, andan isograft was used as control in the same region. The recipients weretreated with either varying concentrations of test compoundsintraperitoneally or orally. Rapamycin was used as a test control.Untreated recipients serve as rejection control. The graft was monitoreddaily and observations were recorded until the graft became dry andformed a blackened scab. This was considered as the rejection day. Themean graft survival time (number of days±S.D.) of the drug treatmentgroup was compared with the control group. The following table shows theresults that were obtained. Results are expressed as the mean survivaltime in days. Untreated (control) pinch skin grafts are usually rejectedwithin 6-7 days. Compounds were tested using a dose of 4 mg/kg.

The adjuvant arthritis standard pharmacological test procedure measuresthe ability of test compounds to prevent immune mediated inflammationand inhibit or treat rheumatoid arthritis. The following brieflydescribes the test procedure used. A group of rats (male inbread WistarLewis rats) are pre-treated with the compound to be tested (1 h prior toantigen) and then injected with Freud's Complete Adjuvant (FCA) in theright hind paw to induce arthritis. The rats are then orally dosed on aMonday, Wednesday, Friday schedule from day 0-14 for a total of doses.Both hind paws are measured on days 16, 23, and 30. The difference inpaw volume (mL) from day 16 to day 0 is determined and a percent changefrom control is obtained. The left hind paw (uninjected paw)inflammation is caused by T-cell mediated inflammation and is recordedin the above table (% change from control). The right hind pawinflammation, on the other hand, is caused by non-specific inflammation.Compounds were tested at a dose of 5 mg/kg. The results are expressed asthe percent change in the uninjected paw at day 16 versus control; themore negative the percent change, the more potent the compound.Rapamycin provided between −70% mid −90% change versus control,indicating that rapamycin treated rats had between 70-90% less immuneinduced inflammation than control rats.

The results obtained in these standard pharmacological test proceduresare provided following the procedure for making the specific compoundsthat were tested.

The results of these standard pharmacological test proceduresdemonstrate immunosuppressive activity both in vitro and in vivo for thecompounds of this invention. The results obtained in the LAF testprocedure indicates suppression of T-cell proliferation, therebydemonstrating the immunosuppressive activity of the compounds of thisinvention. Further demonstration of the utility of the compounds of thisinvention as immunosuppressive agents was shown by the results obtainedin the skin graft and adjuvant arthritis standard pharmacological testprocedures. Additionally, the results obtained in the skin graft testprocedure further demonstrates the ability of the compounds of thisinvention to treat or inhibit transplantation rejection. The resultsobtained in the adjuvant arthritis standard pharmacological testprocedure further demonstrate the ability of the compounds of thisinvention to treat or inhibit rheumatoid arthritis.

Based on the results of these standard pharmacological test procedures,the compounds are useful in the treatment or inhibition oftransplantation rejection such as kidney, heart, liver, lung, bonemarrow, pancreas (islet cells), cornea, small bowel, and skinallografts, and heart valve xenografts; in the treatment or inhibitionof autoimmune diseases such as lupus, rheumatoid arthritis, diabetesmellitus, myasthenia gravis, and multiple sclerosis; and diseases ofinflammation such as psoriasis, dermatitis, eczema, seborrhea,inflammatory bowel disease, pulmonary inflammation (including asthma,chronic obstructive pulmonary disease, emphysema, acute respiratorydistress syndrome, bronchitis, and the like), and eye uveitis.

Because of the activity profile obtained, the compounds of thisinvention also are considered to have antitumor, antifungal activities,and antiproliferative activities. The compounds of this inventiontherefore also useful in treating solid tumors, adult T-cellleukemia/lymphoma, fungal infections, and hyperproliferative vasculardiseases such as restenosis and atherosclerosis. When used forrestenosis, it is preferred that the compounds of this invention areused to treat restenosis that occurs following an angioplasty procedure.When used for this purpose, the compounds of this invention can beadministered prior to the procedure, during the procedure, subsequent tothe procedure, or any combination of the above.

When administered for the treatment or inhibition of the above diseasestates, the compounds of this invention can be administered to a mammalorally, parenterally, intranasally, intrabronchially, transdermally,topically, intravaginally, or rectally.

It is contemplated that when the compounds of this invention are used asan immunosuppressive or antiinflammatory agent, they can be administeredin conjunction with one or more other immunoregulatory agents. Suchother immunoregulatory agents include, but are not limited toazathioprine, corticosteroids, such as prednisone andmethylprednisolone, cyclophosphamide, rapamycin, cyclosporin A, FK-506,OKT-3, and ATG. By combining the compounds of this invention with suchother drugs or agents for inducing immunosuppression or treatinginflammatory conditions, the lesser amounts of each of the agents arerequired to achieve the desired effect. The basis for such combinationtherapy was established by Stepkowski whose results showed that the useof a combination of rapamycin and cyclosporin A at subtherapeutic dosessignificantly prolonged heart allograft survival time. [TransplantationProc. 23: 507 (1991)].

The compounds of this invention can be formulated neat or with apharmaceutical carrier to a mammal in need thereof. The pharmaceuticalcarrier may be solid or liquid. When formulated orally, it has beenfound that 0.01% Tween 80 in PHOSAL PG-50 (phospholipid concentrate with1,2-propylene glycol, A. Nattermann & Cie, GmbH) provides an acceptableoral formulation.

A solid carrier can include one or more substances which may also act asflavoring agents, lubricants, solubilizers, suspending agents, fillers,glidants, compression aids, binders or tablet-disintegrating agents; itcan also be an encapsulating material. In powders, the carrier is afinely divided solid which is in admixture with the finely dividedactive ingredient. In tablets, the active ingredient is mixed with acarrier having the necessary compression properties in suitableproportions ,and compacted in the shape and size desired. The powdersand tablets preferably contain up to 99% of the active ingredient.Suitable solid carriers include, for example, calcium phosphate,magnesium stearate, talc, sugars, lactose, dextrin, starch, gelatin,cellulose, methyl cellulose, sodium carboxymethyl cellulose,polyvinylpyrrolidine, low melting waxes and ion exchange resins.

Liquid carriers are used in preparing solutions, suspensions, emulsions,syrups, elixirs and pressurized compositions. The active ingredient canbe dissolved or suspended in a pharmaceutically acceptable liquidcarrier such as water, an organic solvent, a mixture of both orpharmaceutically acceptable oils or fats. The liquid carrier can containother suitable pharmaceutical additives such as solubilizers,emulsifiers, buffers, preservatives, sweeteners, flavoring agents,suspending agents, thickening agents, colors, viscosity regulators,stabilizers or osmo-regulators. Suitable examples of liquid carriers fororal and parenteral administration include water (partially containingadditives as above, e.g. cellulose derivatives, preferably sodiumcarboxymethyl cellulose solution), alcohols (including monohydricalcohols and polyhydric alcohols, e.g. glycols) and their derivatives,and oils (e.g. fractionated coconut oil and arachis oil). For parenteraladministration, the carrier can also be an oily ester such as ethyloleate and isopropyl myristate. Sterile liquid carders are useful insterile liquid form compositions for parenteral administration. Theliquid carrier for pressurized compositions can be halogenatedhydrocarbon or other pharmaceutically acceptable propellant.

Liquid pharmaceutical compositions which are sterile solutions orsuspensions can be utilized by, for example, intramuscular,intraperitoneal or subcutaneous injection. Sterile solutions can also beadministered intravenously. The compound can also be administered orallyeither in liquid or solid composition form.

The compounds of this invention may be administered rectally in the formof a conventional suppository. For administration by intranasal orintrabronchial inhalation or insufflation, the compounds of thisinvention may be formulated into an aqueous or partially aqueoussolution, which can then be utilized in the form of an aerosol. Thecompounds of this invention may also be administered transdermallythrough the use of a transdermal patch containing the active compoundand a carrier that is inert to the active compound, is non toxic to theskin, and allows delivery of the agent for systemic absorption into theblood stream via the skin. The carrier may take any number of forms suchas creams and ointments, pastes, gels, and occlusive devices. The creamsand ointments may be viscous liquid or semi-solid emulsions of eitherthe oil-in-water or water-in-oil type. Pastes comprised of absorptivepowders dispersed in petroleum or hydrophilic petroleum containing theactive ingredient may also be suitable. A variety of occlusive devicesmay be used to release the active ingredient into the blood stream suchas a semipermiable membrane covering a reservoir containing the activeingredient with or without a carrier, or a matrix containing the activeingredient. Other occlusive devices are known in the literature.

In addition, the compounds of this invention may be employed as asolution, cream, or lotion by formulation with pharmaceuticallyacceptable vehicles containing 0.1-5 percent, preferably 2%, of activecompound which may be administered to a fungally affected area.

The dosage requirements vary with the particular compositions employed,the route of administration, the severity of the symptoms presented andthe particular subject being treated. Based on the results obtained inthe standard pharmacological test procedures, projected daily dosages ofactive compound would be 0.1 μg/kg-100 mg/kg, preferably between0.001-25 mg/kg, and more preferably between 0.01-5 mg/kg. Treatment willgenerally be initiated with small dosages less than the optimum dose ofthe compound. Thereafter the dosage is increased until the optimumeffect under the circumstances is reached; precise dosages for oral,parenteral, nasal, or intrabronchial administration will be determinedby the administering physician based on experience with the individualsubject treated. Preferably, the pharmaceutical composition is in unitdosage form, e.g. as tablets or capsules. In such form, the compositionis sub-divided in unit dose containing appropriate quantities of theactive ingredient; the unit dosage forms can be packaged compositions,for example., packeted powders, vials, ampoules, prefilled syringes orsachets containing liquids. The unit dosage form can be, for example, acapsule or tablet itself, or it can be the appropriate number of anysuch compositions in package form.

The following examples illustrate the preparation and biologicalactivities of representative compounds of this invention.

EXAMPLE 1 Rapamycin 42-ester with (tetrahydropyran-2-yloxy)acetic acid

2,4,6-Trichlorobenzoyl chloride (0.55 mL, 3.51 mmol) was added viasyringe to a solution of the glycolic acid THP-ether (0.562 g, 3.51mmol) and triethylamine (0.49 mL, 3.51 mmol) in 10 mL THF at 0° C. undernitrogen. The mixture was stirred for 4 h at room temperature, and awhite precipitate formed. The white precipitate was removed by vacuumfiltration and the filtrate was concentrated with a stream of nitrogenand warm water bath. The residue was dissolved in 10 mL benzene, thenrapamycin (2.92 g, 3.19 mmol) and DMAP (0.429 g, 3.51 mmol) were addedand the mixture was stirred overnight at room temperature. The mixturewas diluted with EtOAc, washed with cold 1N HCl (aq), saturated NaHCO₃(aq) and brine, dried over MgSO₄, filtered and concentrated to an oilyyellow solid. Flash chromatography (2X with 65% EtOAc-hexane) affordedthe title compound (1.114 g, 33%) as a white solid.

(−)FAB-MS m/z 1055.5 (M⁻), 590.3 (southern fragment), 463.2 (northernfragment). ¹H NMR (400 MHz, d-6 DMSO) δ 4.60 (m, 1 H, C(42)H), 4.66 (m,1H), 4.14 (s, 2H), 3.73 (m, 1H), 3.42 (m, 1H). ¹³C NMR (100.6 MHz, d-6DMSO) δ 169.2, 97.4, 63.5, 61.2, 29.7, 24.8, 18.8.

EXAMPLE 2 Rapamycin 42-ester with hydroxyacetic acid

p-Toluenesulfonic acid (10 mg) was added to a solution of the product ofExample 1 (306 mg, 0.29 mmol) in 10 mL CH₃OH at 0° C. The solution wasstirred 2 h at room temperature, then quenched with saturated NaHCO₃solution. The aqueous phase was extracted 3X with EtOAc and the combinedorganic phases were washed with brine, dried over MgSO₄, filtered andconcentrated to a white solid. Purification by flash chromatography (2Xwith EtOAc) afforded the title compound (145 mg, 51%) as a white solid.

(−) FAB-MS m/z 971.3 (M⁻), 590 (southern fragment), 379.1 (northernfragment). ¹H NMR (400 MHz, d-6 DMSO) δ 4.60 (m, 1H, C(42)H), 3.98 (s,2H). ¹³C NMR (100.6 MHz, d-6 DMSO) δ 172.1, 59.7.

Results obtained in standard pharmacological test procedures:

-   -   LAF IC₅₀: 1.80 nM    -   LAF ratio: 0.83    -   Percent change in adjuvant arthritis versus control: −88%

EXAMPLE 3 Rapamycin 42-ester with2,2-dimethyl-3-(tetrahydropyran-2-yloxy)propionic acid

To a solution of the 2,2-dimethyl-3-hydroxypropionic acid THP-ether(0.319 g, 1.58 mmol) and triethylamine (0.22 mL, 1.58 mmol) in 5 mL dryTHF at 0° C. under nitrogen was added 2,4,6-trichlorobenzoyl chloride(0.25 mL, 1.58 mmol) dropwise via syringe. The mixture was stirred 4.5 hat room temperature. The white precipitate was removed by vacuumfiltration and the filtrate was concentrated with a stream of nitrogenand a warm water bath. The residue was dissolved in 5 mL benzene, thenrapamycin (1.31 g, 1.43 mmol) and DMAP (0.193 g, 1.58 mmol) were added.The mixture was stirred overnight at room temperature, diluted withEtOAc, washed with 1N HCl (aq), saturated NaHCO₃ (aq), H₂O and brine,dried over MgSO₄, filtered and concentrated to a yellow oily solid.Flash chromatography (1X with 60% EtOAc-hexane, 1X with 55%EtOAc-hexane) afforded the title compound (0.356 g, 23%), as a whitesolid.

(−)FAB-MS m/z 1097.7 (M⁻), 590.4 (southern fragment), 505.3 (northernfragment). ¹H NMR (400 MHz, d-6 DMSO) δ 4.55 (m, 1H, C(42H), 4.55 (m,1H), 3.69 (m, 1H), 3.60 (m, 2H), 3.42 (m, 1H), 1.13 (s, 3H), 1.11 (s,3H). ¹³C NMR (100.6 MHz, d-6 DMSO) δ 175.0, 98.0, 73.8, 60.7, 42.6,30.0, 24.9, 22.0, 21.6, 18.7.

Results obtained in standard pharmacological test procedures:

-   -   LAF IC₅₀: 7.10 nM    -   LAF ratio: 0.34

EXAMPLE 4 Rapamycin 42-ester with 3-hydroxy-2,2-dimethylpropionic acid

p-Toluenesulfonic acid (10 mg) was added to a solution of the product ofExample 3 (250 mg, 0.23 mmol) in 10 mL CH₃OH at 0° C. The solution wasstirred 2 hours at room temperature, then quenched with saturated NaHCO₃solution. The aqueous phase was extracted 3X with EtOAc and the combinedorganic phases were washed with brine, dried over MgSO₄, filtered andconcentrated to a white solid. Purification by flash chromatography (2Xwith 75% EtOAc-hexane) afforded the title compound (103 mg, 45%) as awhite solid.

(−) FAB-MS m/z 1013.3 (M³¹), 590.2 (southern fragment), 421.1 (northernfragment). ¹H NMR (400 MHz, d-6 DMSO) δ 4.48 (m, 1H, C(42)H), 3.39 (d,2H), 106 (s, 6H). ¹³C NMR (100.6 MHz, d-6 DMSO) δ 175.5, 68.0, 44.1,21.7.

Results obtained in standard pharmacological test procedures:

-   -   LAF IC₅₀:0.80 nM    -   LAF ratio: 1.25    -   Skin graft survival time: 10.7±0.5 days

EXAMPLES 5 AND 6 Rapamycin 42-ester with2,2-dimethyl[1,3]dioxalane-4-carboxylic acid (Ex. 5) Rapamycin31,42-diester with 2,2-dimethyl[1,3]dioxalane-4-carboxylic acid (EX. 6)

2,4,6-Trichlorobenzoyl chloride (0.56 mL, 3.61 mmol) was added viasyringe to a solution of the 2,3-dihydroxypropionic acid isopropylideneketal (0.527 g, 3.61 mmol) and triethylamine (0.50 mL, 3.61 mmol) in 10mL THF at 0° C. under nitrogen. The mixture was stirred 4 h at roomtemperature. The white precipitate was removed by vacuum filtration andthe filtrate was concentrated with a stream of nitrogen and warm waterbath. The residue was dissolved in 15 mL benzene and rapamycin (3.00 g,3.28 mmol), then DMAP (0.441 g, 3.61 mmol) were added and the mixturewas stirred overnight at room temperature. The mixture was diluted withEtOAc, washed with cold 1N HCl (aq), saturated NaHCO₃ (aq) and brine,dried over MgSO₄, filtered and concentrated to a yellow foam. Flashchromatography on silica gel (gradient elution: 50-60-7-5-100%EtOAc-hexane, 4X with 65% EtOAc-hexane) afforded the title compounds.The less polar 31,42-diester (0.415 g) eluted first and the more polar42-monoester (0.601 g, 16%) eluted second, and were isolated as whitesolids.

EXAMPLE 5

(−)FAB-MS m/z 1041.4 (M⁻), 590.3 (southern fragment), 449.2 (northernfragment). ¹H NMR (400 MHz, d-6 DMSO) δ 4.6 (m, 1H, C(42)H), 4.6 (m,1H), 4.20 (dd, 1H), 3.96 (m, 1H), 1.36 (s, 3H), 1.30 (s, 3H). ¹³C NMR(100.6 MHz, d-6 DMSO) δ 170.5, 110.2, 73.4, 66.6, 25.7, 25,4.

EXAMPLE 6

(−)FAB-MS m/z 1169.6 (M⁻). ¹H NMR (400 MHz, d-6 DMSO) δ 5.3 (m, 1H,C(31)H), 4.6 (m, 1H, C(42)H), 4.6 (m, 2H), 4.19 (t, 1H), 4.13 (t, 1H),3.9 (m, 2H), 1.36 (s, 3H), 1.33 (s, 3H), 1.30 (s, 3H), 1.28 (s, 3H). ¹³CNMR (100.6 MHz, d-6 DMSO) δ 170.5, 169.2, 110.3, 110.2, 73.4, 66.6,66.5, 25.8, 25.7, 25.4, 25.1.

Results obtained in standard pharmacological test procedures:

EXAMPLE 5

-   -   LAF IC₅₀: 1.20 nM    -   LAF ratio: 0.74

EXAMPLE 6

-   -   LAF IC₅₀: 1.30 nM    -   LAF ratio: 0.5

EXAMPLE 7 Rapamycin 42-ester with 2,3-dihydroxypropionic acid

A solution of the product of Example 5 (351 mg, 0.34 mmol) in 10 mL THEand 10 mL 1N HCl was stirred at room temperature for 6 h. The mixturewas diluted with EtOAc, washed with saturated NaHCO₃ solution and brine,dried over MgSO₄, filtered and concentrated to an oil. Flashchromatography (1X with EtOAc, 1X with 10% MeOH-CH₂Cl₂, 1X with 5%MeOH-EtOAc) afforded the title compound (78 mg, 23%) as a white solid.

(−)FAB-MS m/z 1001.2 (M⁻), 590.2 (southern fragment), 409.1 (northernfragment). ¹H NMR (400 MHz, d-6 DMSO) δ 5 4.5 (m, 1H, C(42)H), 3.60 (m,1H), 3.45 (m, 2H).

Results obtained in standard pharmacological test procedures:

-   -   LAF IC₅₀: 1.4 nM    -   LAF ratio: 0.40

EXAMPLE 8 Rapamycin 42-ester with 2.2-dimethyl[1.3dioxane-5-carboxylicacid

2,4,6-Trichlorobenzoyl chloride (0.98 mL, 6.27 mmol) was added viasyringe to a solution of the 2-(hydroxymethyl)-3-hydroxypropionic acidisopropylidene ketal (1.000 g, 6.24 mmol) and triethylamine (0.90 mL,6.46 mmol) in 20 mL, THF at 0° C. under nitrogen. The mixture wasstirred for 4 h at room temperature, and a white precipitate formed. Thewhite precipitate was removed by vacuum filtration and the filtrate wasconcentrated with a stream of nitrogen and warm water bath. The residuewas dissolved in 20 mL benzene, then rapamycin (5.70 g, 6.24 mmol) andDMAP (0.762 g, 6.24 mmol) were added and the mixture was stirredovernight at room temperature. The mixture was diluted with EtOAc,washed with H₂O and brine, dried over MgSO₄, filtered and concentratedto a yellow solid. Flash chromatography (75% EtOAc-hexane) afforded thetitle compound (4.17 g, 63%) as a white solid.

(−)FAB-MS m/z, 1055.8 (M⁻), 590.5 (southern fragment), 463.4 (northernfragment). ¹H NMR (400 MHz, d-6 DMSO) δ 4.55 (m, 1H, C(42)H), 3.95 (m,4H), 1.30 (s, 6H). ¹³C NMR (100.6 MHz, d-6 DMSO) δ 170.1, 97.4, 59.5,24.8, 22.5.

Results obtained in standard pharmacological test procedures:

-   -   LAF IC₅₀: 0.76 nM    -   LAF ratio: 0.45

EXAMPLE 9 Rapamycin 42-ester with 3-hydroxy-2-hydroxymethylpropionicacid

A solution of the product of Example 8 (3.30 g, 3.12 mmol) in 50 mL THFand 25 mL 1N HCl was stirred 2 h at room temperature. The solution wasdiluted with saturated NaHCO₃ solution and extracted with EtOAc (3X).The combined organic phases were washed with saturated NaCl (aq), driedover MgSO₄, filtered and concentrated to a yellow foam. Purification byflash chromatography (1X with EtOAc; 2X with 5% EtOH-EtOAc) afforded thetitle compound (1.68 g, 53%) as a white solid.

(−) FAB-MS m/z 1015.5 (M⁻), 590.3 (southern fragment), 423.3 (northernfragment). ¹H NMR (400 MHz, d-6 DMSO) δ 4.6 (br s, 2H), 4.55 (m, 1H,C(42)H), 3.55 (m, 4H), 2.57-2.53 (m, 1H). ¹³C NMR (100.6 MHz, d-6 DMSO)δ 172.2, 59,3, 51.5.

Results obtained in standard pharmacological test procedures:

-   -   LAF IC₅₀: 0.84 nM    -   LAF ratio: 0.57

EXAMPLE 10 Rapamycin 42-ester with2,2,5-trimethyl[1.3dioxane-5-carboxylic acid

To a solution of the 2,2-bis(hydroxymethyl)propionic acid isopropylideneketal (1.041 g, 5.98 mmol) (prepared according to the procedure ofBruice, J. Am. Chem. Soc. 89:3568 (1967)) and triethylamine (0.83 mL,5.98 mmol) in 20 mL anhydrous THE at 0° C. under nitrogen was added2,4,6-trichlorobenzoyl chloride (0.93 mL, 5.98 mmol) and the resultantwhite suspension was stirred 5 h at room temperature. The precipitatewas removed by vacuum filtration, rinsing the flask and filter cake withan additional 10 mL dry THF. The filtrate was concentrated by rotaryevaporation to a white solid. The residue was dissolved in 20 mL drybenzene, then rapamycin (5.47 g, 5.98 mmol) and DMAP (0.731 g, 5.98retool) were added. After stirring overnight at room temperature, themixture was diluted with EtOAc, washed with H₂O and saturated NaCl (aq),dried over MgSO₄, filtered and evaporated to a yellow oil, Flashchromatography (5X with 60% EtOAc-hexane) afforded the title compound(2.2 g, 34%) as a white solid.

(−)FAB-MS m/z 1069.5 (M⁻), 590.3 (southern fragment), 477.2 (northernfragment). ¹H NMR (400 MHz, d-6 DMSO) δ 4.57 (m, 1H, C(42)H, 4.02 (d,2H), 3.60 (d, 2H), 1.34 (s, 3H), 1.24 (s, 3H), 1.06 (s, 3H). ¹³C NMR(100.6 MHz, d-6 DMSO) δ 173.2, 99.0, 65.0, 22.2, 18.1.

Results obtained in standard pharmacological test procedures:

-   -   LAF IC₅₀: 4.90 nM    -   LAF ratio: 0.41    -   Skin graft survival time: 11.0±1.3 days

EXAMPLE 11 Rapamycin 42-ester with 2,2-bis-(hydroxymethyl)propionic acid

A solution of the product of Example 10 (2.8 g, 2.65 mmol) in 50 mL THFand 25 mL 1N HCl was stirred at room temperature for 4 h. The mixturewas diluted with water and extracted three times with EtOAc. Thecombined organic phases were washed with saturated NaHCO₃ solution,saturated NaCl solution, dried over MgSO₄, filtered and evaporated to ayellow oily solid. Purification by flash chromatography (3X with EtOAc)afforded the title compound (1.6 g, 59%).

(−)FAB-MS m/z 1029.6 (M⁻), 590.4 (southern fragment), 437.3 (northernfragment). ¹H NMR (400 MHz, d-6 DMSO) δ 4.5 (m, 1H, C(42)H), 3.45 (s,4H), 1.04 (s, 3H). ¹³C NMR (100.6 MHz, d-6 DMSO) δ 174.2, 63.7, 63.6,49.9, 16.8.

Results obtained in standard pharmacological test procedures:

-   -   LAF IC₅₀: 0.80 and 1.80 nM    -   LAF ratio: 1.00 and 0.44    -   Skin graft survival time: 11.4±1.5 and 12.0±1.1 days    -   Percent change in adjuvant arthritis versus control: <88%

EXAMPLE 12

-   -   Rapamycin 42-ester with        2,2-dimethyl-5-(2-trimethylsilanylethoxymethyl)[1,3]dioxane-5-carboxylic        acid

2,4,6-Trichlorobenzoyl chloride (0.14 mL, 0.86 mmol) was added viasyringe to a solution of the2,2-bis(hydroxymethyl)-2-(2-trimethylsilylethoxy)propionic acidisopropylidene ketal (0.250 g, 0.86 mmol) and triethylamine (0.12 mL,0.86 mmol) in 2 mL THF at 0° C. under nitrogen. The mixture was stirredfor 4 h at room temperature, and a white precipitate formed. The whiteprecipitate was removed by vacuum filtration and the filtrate wasconcentrated with a stream of nitrogen and warm water bath. The residuewas dissolved in 2 mL benzene, then rapamycin (0.786 g, 0.86 mmol) andDMAP (0.105 g, 0.86 mmol) were added and the mixture was stirredovernight, at room temperature. The mixture was diluted with EtOAc,washed with H₂O and brine, dried over MgSO₄, filtered and concentratedto a yellow solid. Flash chromatography (gradient elution: 40-60-80-100%EtOAc-hexane) afforded the title compound (0.559 g, 54%) as a whitesolid.

(−)FAB-MS m/z 1185.2 (M⁻), 590.1 (southern fragment), 593 (northernfragment). ¹H NMR (400 MHz, d-6 DMSO) δ 4.55 (m, 1H, C(42)H), 3.73 (m,4H), 3.57 (s, 2 H), 3.43 (t, 2H), 1.29 (s, 6H), 0.79 (t, 2H), −0.04 (s,9H). ¹³C NMR (100.6 MHz, d-6 DMSO) δ 171.1, 97.7, 70.2, 68.1, 61.3,46.0, 24.6, 22.1, 14.6, −1.3.

Results obtained in standard pharmacological test procedures:

-   -   LAF IC₅₀: 7.20 nM    -   LAF ratio: 0.05

EXAMPLES 13 and 14 Rapamycin 42-ester with3-methyl-1,5-dioxa-spiro[5.5]undecane 3-carboxylic acid (Ex. 13)Rapamycin 31.42-diester with 3-methyl-1.5-dioxa-spiro[5.5]undecane3-carboxylic acid (Ex. 14)

2,4,6-Trichlorobenzoyl chloride (0.16 mL, 1.0 mmol) was added viasyringe to a solution of the 2,3-dihydroxypropionic acid cyclohexylideneketal (0.214 g, 1.0 mmol) and triethylamine (0.14 mL, 1.0 mmol) in 2.5mL THF at 0 ° C. under nitrogen. The mixture was stirred 4 h at roomtemperature. The white precipitate was removed by vacuum filtration andthe filtrate was concentrated with a stream of nitrogen and warm waterbath. The residue was dissolved in 3 mL benzene and rapamycin (0.457 g,0.5 mmol), then DMAP (0.061 g, 0.5 mmol) were added and the mixture wasstirred overnight at room temperature. The mixture was diluted withEtOAc, washed with cold 1N HCl (aq), saturated NaHCO₃(aq) and brine,dried over MgSO₄, filtered and concentrated to a yellow foam. Flashchromatography on silica gel (45-50% EtOAc-hexane) afforded the titlecompounds. The 31,42-diester (0.168 g, 26%) eluted first and the morepolar 42-monoester (0.301 g, 52%) eluted second, and the products wereisolated as white solids.

EXAMPLE 13

(−)FAB-MS m/z 1109.5 (M⁻), 590.3 (southern fragment), 517.3 (northernfragment). ¹H NMR (400 MHz, d-6 DMSO) δ 4.55 (m, 1H, C(42)H), 3.61 (t,4H), 1.04 (s, 3H). ¹³C NMR (100.6 MHz, d-6 DMSO) δ 173.3, 97.2, 64.2.

EXAMPLE 14

(−)FAB-MS m/z 1305.6 (M⁻). ¹H NMR (400 MHz, d-6 DMSO) δ 5.25 (m, 1H,C(31)H), 4.55 (m, 1H, C(42)H), 3.64-3.54 (m, 8H), 1.05 (s, 3H), 0.97 (s,3H). ¹³C NMR (100.6 MHz, d-6 DMSO) δ 173.2, 172.1, 97.3, 97.2, 64.3,64.2, 63.9.

Results obtained in standard pharmacological test procedures:

EXAMPLE 13

-   -   LAF IC₅₀: 0.6 nM    -   LAF ratio: 2.00

EXAMPLE 14

LAF: inhibited T-cell proliferation by 43% at 0.1 μM

What is claimed is:
 1. A compound of the structure

wherein R¹ and R²are each, independently, hydrogen or—CO(CR³R⁴)_(b)(CR⁵R⁶)_(d)CR⁷R⁸R⁹; R³ and R⁴ are each, independently,hydrogen, alkyl of 1-6 carbon atoms, alkenyl of 2-7 carbon atoms,alkynyl of 2-7 carbon atoms, trifluoromethyl, or —F; R⁵ and R⁶ are each,independently, hydrogen, alkyl of 1-6 carbon atoms, alkenyl of 2-7carbon atoms, alkynyl of 2-7 carbon atoms, —(CR³R⁴)_(f)OR¹⁰, —CF₃, —F,or —CO₂R¹¹, or R⁵ and R⁶ may be taken together to form X or a cycloalkylring of 3-8 carbon atoms that is optionally mono-, di-, ortri-substituted with —(CR³R⁴)_(f)OR¹⁰; R⁷ is hydrogen, alkyl of 1-6carbon atoms, alkenyl of 2-7 carbon atoms, alkynyl of 2--7 carbon atoms,—(CR³R⁴)_(f)OR¹⁰, —CF₃—F, or—CO₂R¹¹; R⁸ and R⁹ are each, independently,hydrogen, alkyl of 1-6 carbon atoms, alkenyl of 2-7 carbon atoms,alkynyl of 2-7 carbon atoms, —(CR³R⁴)_(f)OR¹⁰, —CF₃, —F, or —CO₂R¹¹, orR⁸ and R⁹ may be taken together to form X or a cycloalkyl ring of 3-8carbon atoms that is optionally mono-, di-, or tri-substituted with—(CR³R⁴)_(f)OR¹⁰; R¹⁰ is hydrogen, alkyl of 1-6 carbon atoms, alkenyl of2-7 carbon atoms alkynyl of 2-7 carbon atoms, tri-(alkyl of 1-6 carbonatoms)silyl, tri-(alkyl of 1-6 carbon atoms)silylethyl, triphenylmethyl,benzyl, alkoxymethyl of 2-7 carbon atoms, tri-(alkyl of 1-6 carbonatoms)silylethoxymethyl, chloroethyl, or tetrahydropyranyl; R¹¹ ishydrogen, alkyl of 1-6 carbon atoms, alkenyl of 2-7 carbon atoms,alkynyl of 2-7 carbon atoms, or phenylalkyl of 7-10 carbon atoms; X is5-(2,2-di-(alkyl of 1-6 carbon atoms))[1,3]dioxanyl,5-(2,2-di-(cycloalkyl of 3-8 carbon atoms))[1,3]dioxanyl,4-(2,2-di-(alkyl of 1-6 carbon atoms))[1,3]dioxanyl,4-(2,2-di-(cycloalkyl of 3-8 carbon atoms))[1,3]dioxanyl,4-(2,2-di-(alkyl of 1-6 carbon atoms))[1,3]dioxalanyl, or4-(2,2-di-(cycloalkyl of 3-8 carbon atoms))[1,3]dioxalanyl; b=0-6; d=0-6; and f=0-6 with the proviso that R¹ and R² are both not hydrogen andfurther provided that either R¹ or R² contains at least one—(CR³R⁴)_(f)OR¹⁰, X, or —(CR³R⁴)_(f)OR¹⁰ substituted cycloalkyl of 3-8carbon atoms group, or a pharmaceutically acceptable salt thereof. 2.The compound of claim 1, wherein R² is hydrogen or a pharmaceuticallyacceptable salt thereof.
 3. The compound of claim 2, wherein b=0 and d=0or a pharmaceutically acceptable salt thereof.
 4. The compound of claim3, wherein R⁸ and R⁹ are each, independently hydrogen, alkyl, or—(CR³R⁴⁻)_(f)OR¹⁰, or are taken together to form X or a pharmaceuticallyacceptable salt thereof.
 5. The compound of claim 1 which is rapamycin42-ester with (tetrahydropyran-2-yloxy)acetic acid or a pharmaceuticallyacceptable salt thereof.
 6. The compound of claim 1 which is rapamycin42-ester with hydroxyacetic acid or a pharmaceutically acceptable saltthereof.
 7. The compound of claim 1 which is rapamycin 42-ester with2,2-dimethyl-3-(tetrahydropyran-2-yloxy)propionic acid or apharmaceutically acceptable salt thereof.
 8. The compound of claim 1which is rapamycin 42-ester with 3-hydroxy-2,2-dimethylpropionic acid ora pharmaceutically acceptable salt thereof.
 9. The compound of claim 1which is rapamycin 42-ester with 2,2-dimethyl[1,3]dioxalane-4-carboxylicacid or a pharmaceutically acceptable salt thereof.
 10. The compound ofclaim 1 which is rapamycin 31,42-diester with2,2-dimethyl[1,3]dioxalane-4-carboxylic acid or a pharmaceuticallyacceptable salt thereof.
 11. The compound of claim 1 which is rapamycin42-ester with 2,3-dihydroxypropionic acid or a pharmaceuticallyacceptable salt thereof.
 12. The compound of claim 1 which is rapamycin42-ester with 2,2-dimethyl[1,3]dioxane-5-carboxylic acid or apharmaceutically acceptable salt thereof.
 13. The compound of claim 1which is rapamycin 42-ester with 3-hydroxy-2-hydroxymethylpropionic acidor a pharmaceutically acceptable salt thereof.
 14. The compound of claim1 which is rapamycin 42-ester with2,2,5-trimethyl[1,3]dioxane-5-carboxylic acid or a pharmaceuticallyacceptable salt thereof.
 15. The compound of claim 1 which is rapamycin42-ester with 2,2-bis(hydroxymethyl)propionic acid or a pharmaceuticallyacceptable salt thereof.
 16. The compound of claim 1 Which is rapamycin42-ester with2,2-dimethyl-5-(2-trimethylsilanylethoxymethyl)[1,3]-dioxane-5-carboxylicacid or a pharmaceutically acceptable salt thereof.
 17. The compound ofclaim 1 which is rapamycin 42-ester with3-methyl-1,5-dioxa-spiro[5.5]undecane 3-carboxylic acid or apharmaceutically acceptable salt thereof.
 18. The compound of claim 1which is rapamycin 31,42-diester with3-methyl-1,5-dioxa-spiro[5.5]undecane 3-carboxylic acid or apharmaceutically acceptable salt thereof.
 19. A method of treatingtransplantation rejection or graft vs. host disease in a mammal in needthereof, which comprises administering to said mammal an antirejectioneffective amount of a compound of the structure

wherein R¹ and R² are each, independently, hydrogen or—CO(CR³R⁴)_(b)(CR⁵R⁶)_(d)CR⁷R⁸R⁹; R³ and R⁴ are each, independently,hydrogen, alkyl of 1-6 carbon atoms, alkenyl of 2-7 carbon atoms,alkynyl of 2-7 carbon atoms, trifluoromethyl, or —F; R⁵ and R6 are each,independently, hydrogen, alkyl of 1-6 carbon atoms, alkenyl of 2-7carbon atoms, alkynyl of 2-7 carbon atoms, —(CR³R⁴)_(f)OR¹⁰, —CF₃, —F,or —CO₂R¹¹, or R⁵ and R⁶ may be taken together to form X or a cycloalkylring of 3-8 carbon atoms that is optionally mono-, di-, ortri-substituted with —(CR³R⁴)_(f)OR ¹⁰; R⁷ is hydrogen, alkyl of 1-6carbon atoms, alkenyl of 2-7 carbon atoms, alkynyl of 2-7 carbon atoms,—(CR³R⁴)_(f)OR¹⁰, —CF₃, —F, or —CO₂R¹¹; R⁸ and R⁹ are each,independently, hydrogen, alkyl of 1-6 carbon atoms, alkenyl of 2-7carbon atoms, alkynyl of 2-7 carbon atoms, —(CR³R⁴)_(f)OR¹⁰, —CF₃, —F,or —CO₂R¹¹, or R⁸ and R⁹ may be taken together to form X or a cycloalkylring of 3-8 carbon atoms that is optionally mono-, di-, ortri-substituted with —(CR³R⁴)_(f)OR¹⁰; R¹⁰ is hydrogen, alkyl of 1-6carbon atoms, alkenyl of 2-7 carbon atoms, alkynyl of 2-7 carbon atoms,tri-(alkyl of 1-6 carbon atoms)silyl, tri-(alkyl of 1-6 carbonatoms)silylethyl, triphenylmethyl, benzyl, alkoxymethyl of 2-7 carbonatoms, tri-(alkyl of 1-6 carbon atoms)silylethoxymethyl, chloroethyl, ortetrahydropyranyl; R¹¹ is hydrogen, alkyl of 1-6 carbon atoms, alkenylof 2-7 carbon atoms, alkynyl of 2-7 carbon atoms, or phenylalkyl of 7-10carbon atoms; X is 5-(2,2-di-(alkyl of 1-6 carbon atoms))[1,3]dioxanyl,5-(2,2-di-(cycloalkyl of 3-8 carbon atoms))[1,3]dioxanyl,4-(2,2-di-(alkyl of 1-6 carbon atoms))[1,3]dioxanyl,4-(2,2-di-(cycloalkyl of 3-8 carbon atoms))[1,3]dioxanyl,4-(2,2-di-(alkyl of 1-6 carbon atoms))[1,3]dioxalanyl, or4-(2,2-di-(cycloalkyl of 3-8 carbon atoms))[1,3]dioxalanyl; b=0-6; d=0-6; and f=0-6 with the proviso that R¹ and R² are both not hydrogen andfurther provided that either R¹ or R² contains at least one—(CR³R⁴)_(f)OR¹⁰, X, or —(CR³R⁴)_(f)OR¹⁰ substituted cycloalkyl of 3-8carbon atoms group, or a pharmaceutically acceptable salt thereof.
 20. Amethod of treating a fungal infection in a mammal in need thereof, whichcomprises administering to said mammal an antifungal effective amount ofa compound of the structure

wherein R¹ and R² are each, independently, hydrogen or—CO(CR³R⁴)_(b)(CR⁵R⁶)_(d)CR⁷R⁸R⁹; R³ and R⁴ are each, independently,hydrogen, alkyl of 1-6 carbon atoms, alkenyl of 2-7 carbon atoms,alkynyl of 2-7 carbon atoms, trifluoromethyl, or —F; R⁵ and R⁶ are each,independently, hydrogen, alkyl of 1-6 carbon atoms, alkenyl of 2-7carbon atoms, alkynyl of 2-7 carbon atoms, —(CR³R⁴)_(f)OR¹⁻0,—CF₃, —F,or —CO₂R¹¹, or R⁵ and R⁶ may be taken together to form X or a cycloalkylring of 3-8 carbon atoms that is optionally mono-, di-, ortri-substituted with —(CR³R⁴)_(f)OR¹⁰; R⁷ is hydrogen, alkyl of 1-6carbon atoms, alkenyl of 2-7 carbon atoms, alkynyl of 2-7 carbon atoms,—(CR³R⁴)_(f)OR¹⁰, —CF₃, —F, or —CO₂R₁₁; R⁸ and R⁹ are each,independently, hydrogen, alkyl of 1-6 carbon atoms, alkenyl of 2-7carbon atoms, alkynyl of 2-7 carbon atoms, —(CR³R⁴)_(f)OR¹⁰, —CF₃, or—F, —CO₂R¹¹, or R⁸ and R⁹ may be taken together to form X or acycloalkyl ring of 3-8 carbon atoms that is optionally mono-, di-, ortri-substituted with —(CR³R⁴)_(f)OR¹⁰; R¹⁰ is hydrogen, alkyl of 1-6carbon atoms, alkenyl of 2-7 carbon atoms, alkynyl of 2-7 carbon atoms,tri-(alkyl of 1-6 carbon atoms)silyl, tri-(alkyl of 1-6 carbonatoms)silylethyl, triphenylmethyl, benzyl, alkoxymethyl of 2-7 carbonatoms, tri-(alkyl of 1-6 carbon atoms)silylethoxymethyl, chloroethyl, ortetrahydropyranyl; R¹¹ is hydrogen, alkyl of 1-6 carbon atoms, alkenylof 2-7 carbon atoms, alkynyl of 2-7 carbon atoms, or phenylalkyl of 7-10carbon atoms; X is 5-(2,2-di-(alkyl of 1-6 carbon atoms))[1,3]dioxanyl,5-(2,2-di-(cycloalkyl of 3-8 carbon atoms))[1,3]dioxanyl,4-(2,2-di-(alkyl of 1-6 carbon atoms))[1,3]dioxanyl,4-(2,2-di-(cycloalkyl of 3-8 carbon atoms))[1,3]dioxanyl,4-(2,2-di-(alkyl of 1-6 carbon atoms))[1,3]dioxalanyl, or4-(2,2-di-(cycloalkyl of 3-8 carbon atoms))[1,3]dioxalanyl; b=0-6;d=0-6; and d=0-6 with the proviso that R¹ and R² are both not hydrogenand further provided that either R¹ or R² contains at least one—(CR³R⁴)_(f)OR¹⁰, X, or —(CR³R⁴)_(f)OR¹⁰ substituted cycloalkyl of 3-8carbon atoms group, or a pharmaceutically acceptable salt thereof.
 21. Amethod of treating rheumatoid arthritis in a mammal in need thereof,which comprises administering to said mammal an antiarthritis effectiveamount of a compound of the structure

wherein R¹ and R² are each, independently, hydrogen or—CO(CR³R⁴)_(b)(CR⁵R⁶)_(d)CR⁷R⁸R⁹; R³ and R⁴ are each, independently,hydrogen, alkyl of 1-6 carbon atoms, alkenyl of 2-7 carbon atoms,alkynyl of 2-7 carbon atoms, trifluoromethyl, or —F; R⁵ and R⁶ are each,independently, hydrogen, alkyl of 1-6 carbon atoms, alkenyl of 2-7carbon atoms, alkynyl of 2-7 carbon atoms, —(CR³R⁴))_(f)OR¹⁰, —CF₃, —F,or —CO₂R¹¹, or R⁵ and R⁶ may be taken together to form X or a cycloalkylring of 3-8 carbon atoms that is optionally mono-, di-, ortri-substituted with —(CR³R⁴)_(f)OR¹⁰; R⁷ is hydrogen, alkyl of 1-6carbon atoms, alkenyl of 2-7 carbon atoms, alkynyl of 2-7 carbon atoms,—(CR³R⁴)_(f)OR¹⁰, —CF₃, —F, or —CO₂R¹¹; R⁸ and R⁹ are each,independently, hydrogen, alkyl of 1-6 carbon atoms, alkenyl of 2-7carbon atoms, alkynyl of 2-7 carbon atoms, —(CR³R⁴)_(f)OR¹⁰, —CF₃, —F,or —CO₂R¹¹, or R⁸ and R⁹ may be taken together to form X or a cycloalkylring of 3-8 carbon atoms that is optionally mono-, di-, ortri-substituted with —(CR³R⁴)_(f)OR¹⁰; R¹⁰ is hydrogen, alkyl of 1-6carbon atoms, alkenyl 2-7 carbon atoms, alkynyl of 2-7 carbon atoms,tri-(alkyl of 1-6 carbon atoms)silyl, tri-(alkyl of 1-6 carbonatoms)silylethyl, triphenylmethyl, benzyl, alkoxymethyl of 2-7 carbonatoms, tri-(alkyl of 1-6 carbon atoms)silylethoxymethyl, chloroethyl, ortetrahydropyranyl; R¹¹ is hydrogen, alkyl of 1-6 carbon atoms, alkenylof 2-7 carbon atoms, alkynyl of 2-7 carbon atoms, or phenylalkyl of 7-10carbon atoms; X is 5-(2,2di-(alkyl of 1-6 carbon atoms))[1,3]dioxanyl,5-(2,2-di-(cycloalkyl of 3-8 carbon atoms))[1,3]dioxanyl,4-(2,2-di-(alkyl of 1-6 carbon atoms))[1,3]dioxanyl,4-(2,2-di-(cycloalkyl of 3-8 carbon atoms))[1,3]dioxanyl,4-(2,2-di-(alkyl of 1-6 carbon atoms))[1,3]dioxalanyl, or4-(2,2-di-(cycloalkyl of 3-8 carbon atoms))[1,3]dioxalanyl; b=0-6;d=0-6; and f=0-6 with the proviso that R¹ and R² are both not hydrogenand further provided that either R¹ or R² contains at least one—(CR³R⁴)_(f)OR¹⁰, X, or —(CR³R⁴)_(f)OR¹⁰ substituted cycloalkyl of 3-8carbon atoms group, or a pharmaceutically acceptable salt thereof.
 22. Amethod of treating restenosis in a mammal in need thereof, whichcomprises administering to said mammal an antiproliferative effectiveamount of a compound of the structure

wherein R¹ and R² are each, independently, hydrogen or—CO(CR³R⁴)_(b)CR⁵R⁶)_(d)CR⁷R⁸R⁹; R³ and R⁴ are each, independently,hydrogen, alkyl of 1-6 carbon atoms, alkenyl of 2-7 carbon atoms,alkynyl of 2-7 carbon atoms, trifluoromethyl, or —F; R⁵ and R⁶ are each,independently, hydrogen, alkyl of 1-6 carbon atoms, alkenyl of 2-7carbon atoms, alkynyl of 2-7 carbon atoms, —(CR³R⁴)_(f)OR¹⁰, —CF₃, —F,or —CO₂R¹¹, or R⁵ and R⁶ may be taken together to form X or a cycloalkylring of 3-8 carbon atoms that is optionally mono-, di-, ortri-substituted with —(CR³R⁴)_(f)OR¹⁰; R⁷ is hydrogen, alkyl of 1-6carbon atoms, alkenyl of 2-7 carbon atoms, alkynyl of 2-7 carbon atoms,—(CR³R⁴)_(f)OR¹⁰, —CF₃, —F, or —CO₂R¹¹; R⁸ and R⁹ are each,independently, hydrogen, alkyl of 1-6 carbon atoms, alkenyl of 2-7carbon atoms, alkynyl of 2-7 carbon atoms, —(CR³R⁴)_(f)OR¹⁰, —CF₃, —F,or —CO₂R¹¹, or R⁸ and R⁹ may be taken together to form X or a cycloalkylring of 3-8 carbon atoms that is optionally mono-, di-, ortri-substituted with —(CR³R⁴)_(f)OR¹⁰; R¹⁰ is hydrogen, alkyl of 1-6carbon atoms, alkenyl of 2-7 carbon atoms, alkynyl of 2-7 carbon atoms,tri-(alkyl of 1-6 carbon atoms)silyl, tri-(alkyl of 1-6 carbonatoms)silylethyl, triphenylmethyl, benzyl, alkoxymethyl of 2-7 carbonatoms, tri-(alkyl of 1-6 carbon atoms)silylethoxymethyl, chloroethyl, ortetrahydropyranyl; R¹¹ is hydrogen, alkyl of 1-6 carbon atoms, alkenylof 2-7 carbon atoms, alkynyl of 2-7 carbon atoms, or phenylalkyl of 7-10carbon atoms; X is 5-(2,2-di-(alkyl of 1-6 carbon atoms))[1,3]dioxanyl,5-(2,2-di-(cycloalkyl of 3-8 carbon atoms))[1,3]dioxanyl,4-(2,2-di-(alkyl of 1-6 carbon atoms))[1,3]dioxanyl,4-(2,2-di-(cycloalkyl of 3-8 carbon atoms))[1,3]dioxanyl,4-(2,2-di-(alkyl of 1-6 carbon atoms))[1,3]dioxalanyl, or4-(2,2-di-(cycloalkyl of 3-8 carbon atoms))[1,3]dioxalanyl; b=0-6;d=0-6; and f=0-6 with the proviso that R¹ and R² are both not hydrogenand further provided that either R¹ or R² contains at least one—(CR³R⁴)_(f)OR¹⁰, X, or —(CR³R⁴)_(f)OR¹⁰ substituted cycloalkyl of 3-8carbon atoms group, or a pharmaceutically acceptable salt thereof.
 23. Amethod of treating pulmonary inflammation in a mammal in need thereof,which comprises administering to said mammal an antiinflammatoryeffective amount of a compound of the structure

wherein R¹ and R² are each, independently, hydrogen or—CO(CR³R⁴)_(b)(CR⁵R⁶)_(d)CR⁷R⁸R⁹; R³ and R⁴ are each, independently,hydrogen, alkyl of 1-6 carbon atoms, alkenyl of 2-7 carbon atoms,alkynyl of 2-7 carbon atoms, trifluoromethyl, or —F; R⁵ and R⁶ are each,independently, hydrogen, alkyl of 1-6 carbon atoms, alkenyl of 2-7carbon atoms, alkynyl of 2-7 carbon atoms, —(CR³R⁴)_(f)OR¹⁰, —CF₃, —F,or —CO₂R¹¹, or R⁵ and R⁶ may be taken together to form X or a cycloalkylring of 3-8 carbon atoms that is optionally mono-, di-, ortri-substituted with —(CR³R⁴)_(f)OR¹⁰; R⁷ is hydrogen, alkyl of 1-6carbon atoms, alkenyl of 2-7 carbon atoms, alkynyl of 2-7 carbon atoms,—(CR³R⁴)_(f)OR¹⁰, —CF₃, —F, or —CO₂R¹¹; R⁸ and R⁹ are each,independently, hydrogen, alkyl of 1-6 carbon atoms, alkenyl of 2-7carbon atoms, alkynyl of 2-7 carbon atoms, —(CR³R⁴)_(f)OR¹⁰, —CF₃, —F,or —CO₂R¹¹, or R⁸ and R⁹ may be taken together to form X or a cycloalkylring of 3-8 carbon atoms that is optionally mono-, di-, ortri-substituted with —(CR³R⁴)_(f)OR¹⁰; R¹⁰ is hydrogen, alkyl of 1-6carbon atoms, alkenyl of 2-7 carbon atoms, alkynyl of 2-7 carbon atoms,tri-(alkyl of 1-6 carbon atoms)silyl, tri-(alkyl of 1-6 carbonatoms)silylethyl, triphenylmethyl, benzyl, alkoxymethyl of 2-7 carbonatoms, tri-(alkyl of 1-6 carbon atoms)silylethoxymethyl, chloroethyl, ortetrahydropyranyl; R¹¹ is hydrogen, alkyl of 1-6 carbon atoms, alkenylof 2-7 carbon atoms, alkynyl of 2-7 carbon atoms, or phenylalkyl of 7-10carbon atoms; X is 5-(2,2-di-(alkyl of 1-6 carbon atoms))[1,3]dioxanyl,5-(2,2-di-(cycloalkyl of 3-8 carbon atoms))[1,3]dioxanyl,4-(2,2-di-(alkyl of 1-6 carbon atoms))[1,3]dioxanyl,4-(2,2-di-(cycloalkyl of 3-8 carbon atoms))[1,3]dioxanyl,4-(2,2-di-(alkyl of 1-6 carbon atoms))[1,3]dioxalanyl, or4-(2,2-di-(cycloalkyl of 3-8 carbon atoms))[1,3]dioxalanyl; b=0-6;d=0-6; and f=0-6 with the proviso that R¹ and R² are both not hydrogenand further provided that either R¹ or R² contains at least one—(CR³R⁴)_(f)OR¹⁰, X, or —(CR³R⁴)_(f)OR¹⁰ substituted cycloalkyl of 3-8carbon atoms group, or a pharmaceutically acceptable salt thereof.
 24. Apharmaceutical composition which comprises a compound of the structure

wherein R¹ and R² are each, independently, hydrogen or—CO(CR³R⁴)_(b)(CR⁵R⁶)_(d)CR⁷R⁸R⁹; R³ and R⁴ are each, independently,hydrogen, alkyl of 1-6 carbon atoms, alkenyl of 2-7 carbon atoms,alkynyl of 2-7 carbon atoms, trifluoromethyl, or —F; R⁵ and R⁶ are each,independently, hydrogen, alkyl of 1-6 carbon atoms, alkenyl of 2-7carbon atoms, alkynyl of 2-7 carbon atoms, —(CR³R⁴)_(f)OR¹⁰, —CF₃, —F,or —CO₂R¹¹, or R⁵ and R⁶ may be taken together to form X or a cycloalkylring of 3-8 carbon atoms that is optionally mono-, di-, ortri-substituted with —(CR³R⁴)_(f)OR¹⁰; R⁷ is hydrogen, alkyl of 1-6carbon atoms, alkenyl of 2-7 carbon atoms, alkynyl of 2-7 carbon atoms,—(CR³R⁴)_(f)OR¹⁰, —CF₃, —F, or —CO₂R¹¹; R⁸ and R⁹ are each,independently, hydrogen, alkyl of 1-6 carbon atoms, alkenyl of 2-7carbon atoms, alkynyl of 2-7 carbon atoms, —(CR³R⁴)_(f)OR¹⁰, —CF₃—F, or—CO₂R¹¹, or R⁸ and R⁹ may be taken together to form X or a cycloalkylring of 3-8 carbon atoms that is optionally mono-, di-, ortri-substituted with —(CR³R⁴)_(f)OR¹⁰; R¹⁰ is hydrogen, alkyl of 1-6carbon, atoms, alkenyl of 2-7 carbon atoms, alkynyl of 2-7 carbon atoms,tri-(alkyl of 1-6 carbon atoms)silyl, tri-(alkyl of 1-6 carbonatoms)silylethyl, triphenylmethyl, benzyl, alkoxymethyl of 2-7 carbonatoms, tri-(alkyl of 1-6 carbon atoms)silylethoxymethyl, chloroethyl, ortetrahydropyranyl; R¹¹ is hydrogen, alkyl of 1-6 carbon atoms, alkenylof 2-7 carbon atoms, alkynyl of 2-7 carbon atoms, or phenylalkyl of 7-10carbon atoms; X is 5-(2,2-di-(alkyl of 1-6 carbon atoms))[1,3]dioxanyl,5-(2,2-di-(cycloalkyl of 3-8 carbon atoms))[1,3]dioxanyl,4-(2,2-di-(alkyl of 1-6 carbon atoms))[1,3]dioxanyl,4-(2,2-di-(cycloalkyl of 3-8 carbon atoms))[1,3]dioxanyl,4-(2,2-di-(alkyl of 1-6 carbon atoms))[1,3]dioxalanyl, or4-(2,2-di-(cycloalkyl of 3-8 carbon atoms))[1,3]dioxalanyl; b=0-6; d=0-6; and f=0-6 with the proviso that R¹ and R² are both not hydrogenand further provided that either R¹ or R² contains at least one—(CR³R⁴)_(f)OR¹⁰, X, or —(CR³R⁴)_(f)OR¹⁰ substituted cycloalkyl of 3-8carbon atoms group, or a pharmaceutically acceptable salt thereof, and apharmaceutical carrier.
 25. The compound of claim 1, wherein saidcompound is:


26. The pharmaceutical composition of claim 24, wherein R¹ is—CO(CR³R⁴)_(b)(CR⁵R⁶)_(d)CR⁷R⁸R⁹; b=0; d=0; R⁷ is methyl; R⁸ is—(CR³R⁴)_(f)OR¹⁰; R⁹ is —(CR³R⁴)_(f)OR¹⁰; each R³ is hydrogen; each R⁴is hydrogen; each R¹⁰ is hydrogen; each f=1; and R² is hydrogen.